To unlock this achievement, go to the "Playlist" tab and press DPad-Down or A and scroll to the end right and pick the tab that says "Cross Game".
From here you want to choose "The Master Chief Saga" playlist and choose to accept the options (unless you want to turn on time and scoring which works towards par time and par score achievements).
Another thing you should note is that these don't have to be completed in one sitting so you don't need to worry about that as there is a resume option whenever you want to leave and do Somthing else. Also the campaign is set to normal difficulty and can't be changed just as the skulls are set to 0 and can't be equipped which means skulls like infinite ammo can't be used in this playlist.